Seed storage proteins in coffee

Abstract

It has been reported that Coffea arabica seeds contain as the main reserve protein, a legumin-like protein, constituted of two subunits, alpha and beta, of approximately 35 and 20 kDa. In this work the seed proteins of several coffee species and varieties were investigated by SDS-PAGE and gel filtration. No differences were observed in the electrophoretic profiles among varieties of C. arabica, however, marked differences were observed among species, or even among individuals of some species. In general, the molecular weight of the subunits alpha and beta accounted for a monomer of 48 to 62 kDa. However, native molecular weight obtained by gel filtration showed that for most of the species there is association of 6 of such proteins, in a hexamer. The most marked difference was observed for C. canephora and C. racemosa. The former clearly showing isoforms of the subunits, and the later showing absence of the beta subunit. The influence of proteases in this observations is discussed.

Cytology, biochemistry and molecular changes during coffee fruit development

“…Comparison of amino acid sequences of 11S protein deduced from cloned full-length cDNAs reveals the existence of some differences that could not explain the variations of pI and of molecular weight usually observed by SDS-PAGE (Acuña et al, 1999;Baú et al, 2001) or 2D-gel electrophoresis (Rogers et al, 1999a). At the amino acid level, 11S storage proteins are relatively rich in glutamine, glycine, leucine and acid glutamic amino acid residues, respectively with 11 %, 10 %, 9 % and 7.5 % of total molecular weight.…”

“…This argues for a little influence of 11S storage proteins in the control of the pool of free amino acids. However, differences of 11S-protein profiles (SDS-PAGE and 2D-gel electrophoresis) were observed between Arabica and Robusta, as for Ugandan and Congolese varieties (Rogers et al, 1999a), and also in other species, such as C. liberica and dewevrei (Baú et al, 2001), suggesting the existence of several types of 11S proteins in the coffee genus.…”

“…Caturra, protein content represents 10 % of dry weight with 45 % of them being related to 11S legumin storage proteins (Rogers et al, 1999a). By SDS-PAGE (SDS-polyacrylamide gel electro-phoresis) analysis, Baú et al (2001) identified the presence of 11S-type storage proteins in various coffee species, except in C. racemosa where storage proteins of lower molecular weight were observed. Independent of the coffee species studied (Arabica or Robusta), 11S storage proteins were not detected in perisperm tissue (figure 3), but specifically at the time of rapid endosperm expansion (Rogers et al 1999a).…”

Seed germination and seedling development in response to submergence in tree species of the Central Amazonian floodplains

“…The protein content stored in the seed was low (mean value 1.5 %) and similar to those reported by Parolin et al (2010) in a review study on Amazonian species belonging to 20 different families. Although low protein values are common in seeds of native species ( Baú et al 2001 ; da Silva Ferreira et al 2009 ), these compounds are key sources of nitrogen and sulfur for the embryo and are needed for nucleic acid and amino acid synthesis, and thus for the synthesis of new proteins and enzymes ( Shewry et al 1995 ; Buckeridge et al 2004 ). In the case of seeds of flooded plants, the reserve proteins may also contribute to the synthesis of adaptive anaerobic metabolic enzymes, since most of the species we studied germinated and produced seedlings under water.…”

Influence of air temperature on proteinase activity and beverage quality in Coffea arabica

“…This fi nding is particularly interesting because the 11S globulin is the main storage protein in coffee seeds (Acuña et al 1999. The electrophoretic profi le of protein extracts shows that this storage protein is predominant in several cultivars and coffee species (Baú et al 2001). …”